Brake structure of a brake valve

Abstract

The application provides a brake structure of a brake valve and belongs to the technical field of brake valves. The brake structure of the brake valve solves the problem of poor brake stability. The brake structure of the brake valve is characterized in that a main piston is slidably connected in a lower valve body, a follow-up piston is slidably connected in an upper valve body, the follow-up piston abuts against the main piston, the brake structure comprises an auxiliary piston, the auxiliary piston is slidably connected in the upper valve body, the inner cavity of the upper valve body is divided into a front cavity and a rear cavity by the auxiliary piston, the follow-up piston is located in the front cavity, a pair of oil inlet ports and brake oil ports are formed in the cavity walls of the front cavity and the rear cavity, when the follow-up piston moves towards the auxiliary piston, a rear axle pressure cavity for generating brake pressure is formed between one end of the auxiliary piston and the follow-up piston, and when the auxiliary piston moves away from the follow-up piston, a front axle pressure cavity for generating brake pressure is formed between the other end of the auxiliary piston and the inner cavity wall of the upper valve body. The brake structure of the brake valve has the advantage of improving brake stability.

Description

Technical Field

[0001] This invention belongs to the field of brake valve technology and relates to a braking structure for a brake valve. Background Technology

[0002] The braking system of wheeled engineering vehicles typically uses a fully hydraulic brake valve as the core control element. The brake valve includes an oil inlet and a working oil port. In the initial state, the oil inlet and the working oil port are connected. When the driver presses the brake pedal, the piston moves forward, closing the oil inlet and forming a pressure chamber in the valve body. The piston continues to move forward, squeezing the oil in the pressure chamber, which increases the oil pressure. The high-pressure oil is output to the wheel brake through the working oil port, generating braking force.

[0003] During braking, the pressure chamber must be kept sealed. This sealing relies primarily on the sealing ring on the piston. If this sealing ring fails due to long-term wear, aging, or accidental damage, the pressure chamber cannot maintain a tight seal. In this case, piston movement will cause high-pressure oil to leak from the point of seal failure, preventing pressure build-up in the pressure chamber and resulting in the brake pedal being depressurized and loss of braking force. To address the problem of braking failure due to pressure chamber seal failure, those skilled in the art can easily conceive of addressing the issue through the sealing structure, such as using a double-seal structure or selecting a more wear-resistant material for the sealing ring. This allows the second sealing ring to continue sealing the pressure chamber even if the first seal fails. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in the prior art by proposing a braking structure for a braking valve, thereby solving the technical problem of poor braking stability.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A braking structure for a brake valve, the brake valve comprising a lower valve body and an upper valve body, wherein a main piston is slidably connected within the lower valve body, and a follower piston is slidably connected within the upper valve body, the follower piston abutting against the main piston, characterized in that the braking structure includes an auxiliary piston, the auxiliary piston being slidably connected within the upper valve body, and the auxiliary piston dividing the inner cavity of the upper valve body into a front cavity and a rear cavity, the follower piston being located in the front cavity, and both the front cavity and the rear cavity having a pair of oil inlets and brake oil ports on their cavity walls; when the follower piston moves toward the auxiliary piston, a rear axle pressure chamber for generating braking pressure is formed between one end of the auxiliary piston and the follower piston, the rear axle pressure chamber communicating only with the brake oil port of the front cavity; when the auxiliary piston moves away from the follower piston, a front axle pressure chamber for generating braking pressure is formed between the other end of the auxiliary piston and the inner cavity wall of the upper valve body, the front axle pressure chamber communicating only with the brake oil port of the rear cavity.

[0007] This application adds an auxiliary piston to the upper valve body, dividing the inner cavity of the upper valve body into a front chamber and a rear chamber. A pair of oil inlets and brake ports are provided on the walls of both the front and rear chambers. The front chamber forms a rear axle pressure chamber that communicates only with the brake ports. The movement of the follower piston pressurizes the oil in the rear axle pressure chamber, and the pressurized oil is output to the brake from the brake ports in the front chamber. Similarly, the rear chamber forms a front axle pressure chamber that communicates only with the brake ports. The movement of the auxiliary piston pressurizes the oil in the front axle pressure chamber, and the pressurized oil is output to the brake from the brake ports in the rear chamber. Thus, the brake valve of this application can form two pressure chambers. In practical applications, the brake ports of the front chamber are connected to the rear wheel brakes of a wheeled vehicle, and the brake ports of the rear chamber are connected to the front wheel brakes of the wheeled vehicle. This allows the brake valve of this application to form two independent braking circuits. Even if one braking circuit fails due to leakage in the pressure chamber, the other braking circuit can still ensure braking effectiveness, thereby improving braking stability.

[0008] In the braking structure of the aforementioned brake valve, the inner wall of the upper valve body has an outwardly protruding, annular shoulder. One side of the shoulder has a first limiting surface facing the auxiliary piston. One end of the auxiliary piston abuts against the first limiting surface, and this end is fitted with a first sealing ring that abuts against the inner wall of the upper valve body. The first sealing ring separates the inner cavity of the upper valve body, forming the aforementioned front and rear chambers. When the brake valve is in its initial state, the auxiliary piston abuts against the first limiting surface, thus determining the initial position of the auxiliary piston within the valve body. The first sealing ring moves with the auxiliary piston, causing the front and rear chambers to change accordingly. This structure maximizes the utilization of the inner cavity of the upper valve body, ensuring the volume of the rear axle pressure chamber and the front axle pressure chamber, thereby guaranteeing braking stability.

[0009] In the braking structure of the aforementioned brake valve, a first annular groove is formed on the outer peripheral wall of the auxiliary piston. The first sealing ring is located within the first annular groove. The longitudinal section of the first sealing ring is U-shaped, and the opening of the first sealing ring faces the direction of the follower piston. The auxiliary piston and the upper valve body have a communication structure that connects the front chamber and the first annular groove. This structure introduces the oil in the front chamber into the opening of the first sealing ring through the communication structure, causing the first sealing ring to be stretched laterally, ensuring the sealing between the front and rear chambers, thereby ensuring braking stability.

[0010] In the braking structure of the aforementioned brake valve, the connecting structure includes a notch formed on the protruding surface of the shoulder, the notch extending to the first limiting surface, the brake oil port of the front cavity communicating with the notch, a drainage gap between one end of the auxiliary piston and the cavity wall of the upper valve body, the drainage gap communicating with the notch and the first annular groove, the groove width of the first annular groove along the axial direction of the auxiliary piston being greater than the thickness of the first sealing ring along the axial direction of the auxiliary piston, when the auxiliary piston moves away from the follower piston, the groove wall of the first annular groove can completely block the opening of the first sealing ring. The width of the first annular groove along the axial direction of the auxiliary piston is greater than the thickness of the first sealing ring along the axial direction of the auxiliary piston. When the auxiliary piston is in the initial state, there is a gap between the groove wall of the first annular groove and the side of the first sealing ring with an opening. The drainage gap guides the oil flowing through the notch in the front cavity to enter the opening of the first sealing ring, and the first sealing ring opens. When the auxiliary piston moves away from the follower piston, the auxiliary piston moves relative to the first sealing ring until the groove wall of the first annular groove abuts against the side of the first sealing ring with an opening, so that the opening of the first sealing ring is completely blocked. The auxiliary piston drives the first sealing ring to move. During the movement of the auxiliary piston, the U-shaped cavity of the first sealing ring is filled with oil, so that the first sealing ring is in an open state, ensuring the sealing between the front cavity and the rear cavity, thereby improving braking stability.

[0011] In the braking structure of the aforementioned brake valve, a second annular sealing ring is provided on the wall of the front chamber. The second sealing ring is located on the other side of the shoulder. When the outer peripheral wall of the follower piston abuts against the inner ring of the second sealing ring, the aforementioned rear axle pressure chamber is formed between one end of the auxiliary piston and the follower piston. This structure makes reasonable use of the internal cavity space of the upper valve body.

[0012] In the braking structure of the aforementioned brake valve, a compression spring and a third sealing ring are fitted onto the end of the auxiliary piston away from the follower piston. The longitudinal section of the third sealing ring is D-shaped. The outer ring of the third sealing ring abuts against the cavity wall of the rear chamber, and there is a gap between the inner ring and the auxiliary piston. One end of the compression spring acts on the auxiliary piston, and the other end acts on one side of the third sealing ring. The auxiliary piston also has a second limiting surface. There is an oil-blocking gap between the second limiting surface and the other side of the third sealing ring, which communicates with the oil inlet of the rear chamber. When the auxiliary piston moves away from the follower piston, the second limiting surface abuts against the other side of the third sealing ring, so that the end of the auxiliary piston and the inner cavity wall of the upper valve body form the aforementioned front axle pressure chamber. This structure combines the movement trajectory of the auxiliary piston with the structural features of the third sealing ring. Because the outer ring of the third sealing ring abuts against the cavity wall of the rear chamber, when the second limiting surface does not abut against the side of the third sealing ring, the auxiliary piston moves relative to the third sealing ring, thereby eliminating the oil blocking gap. At the same time, the third sealing ring abuts against the second limiting surface under the elastic force of the compression spring, ensuring the stability of the contact between the second limiting surface and the third sealing ring, that is, ensuring the sealing of the front axle pressure chamber, thereby ensuring braking stability.

[0013] In the braking structure of the aforementioned brake valve, the auxiliary piston has a cylindrical contraction section and a conical guide section. The third sealing ring is fitted onto the contraction section. The large end face of the guide section is the aforementioned second limiting surface. The auxiliary piston also has a third limiting surface located at the oil inlet of the rear chamber. A flow-limiting element is fitted over the guide section. The flow-limiting element is slidably connected between the third sealing ring and the third limiting surface. An oil control gap is formed between the flow-limiting element and the guide section, connecting the oil inlet of the rear chamber and the oil blocking gap. When oil enters the oil inlet of the rear chamber, the flow-limiting element slides towards the third sealing ring under the action of the oil, increasing the oil inlet diameter. When the flow-limiting element moves back under the action of the third sealing ring, it limits the flow of oil flowing towards the oil blocking gap, minimizing the impact of the oil on the third sealing ring and reducing the size of the opening that the third sealing ring needs to seal, further improving the sealing performance of the front axle pressure chamber, thereby ensuring braking stability.

[0014] In the braking structure of the aforementioned brake valve, the auxiliary piston also has a sliding section that abuts against the cavity wall of the rear chamber. The sliding section is connected to the small end of the guide section to form the aforementioned third limiting surface. The auxiliary piston has a flow-guiding hole that extends radially from the sliding section to the guide section. The flow-guiding hole connects the oil inlet of the rear chamber and the oil control gap. The cross-section of the flow-limiting element is annular. The outer end of the flow-limiting element is clearance-fitted with the upper valve body, and the inner ring of the flow-limiting element has a second annular groove. The outer end of the flow restrictor is fitted with the upper valve body with a clearance, allowing the flow restrictor to move relative to the auxiliary piston. When oil enters the rear chamber through the inlet, the flow restrictor, with the help of the flow restriction gap, moves relative to the auxiliary piston towards the third sealing ring along with the oil. The second annular groove moves to the large end of the guide section. At this time, the second annular groove increases the cross-sectional area at the connection between the oil control gap and the oil blocking gap, accelerating the oil intake speed. Furthermore, under the elastic force of the compression spring, the third sealing ring drives the flow restrictor to move back. The flow restrictor, under the action of the oil, abuts against the third sealing ring, achieving bidirectional contact. At this time, the cross-sectional area at the connection between the oil control gap and the oil blocking gap decreases. This structure improves the sealing performance of the rear axle pressure chamber, thereby further ensuring braking stability.

[0015] In the braking structure of the aforementioned brake valve, the auxiliary piston also has an extension section connected to the sliding section. An oil storage gap exists between the extension section and the rear chamber wall. A pressure relief groove is provided on the sliding section, connecting the oil storage gap and the drainage hole. Because the auxiliary piston is slidably connected to the upper valve body, the extension section reduces the contact area between the auxiliary piston and the lower valve body. Oil retained in the oil storage gap can be discharged through the pressure relief groove. This structure minimizes the movement resistance of the auxiliary piston, ensuring smooth movement and thus improving the braking stability of the brake valve.

[0016] In the aforementioned braking structure of the brake valve, the braking structure further includes a second compression spring located in the front chamber, with its two ends acting on the follower piston and the auxiliary piston, respectively. The braking structure also includes a third compression spring located in the rear chamber, with its two ends acting on the auxiliary piston and the rear chamber wall, respectively. The elastic force of the third compression spring is greater than that of the second compression spring. This structure, by adjusting the elastic forces of the second and third compression springs, ensures that the front chamber builds pressure before the rear chamber. That is, the rear axle pressure chamber can output braking pressure to the corresponding brake port before the front axle pressure chamber. This connects the rear axle pressure chamber to the rear wheel brakes of the wheeled vehicle, and the front axle pressure chamber to the front wheel brakes of the wheeled vehicle, ensuring that the rear wheel brakes precede the front wheel brakes, thereby improving braking stability.

[0017] Compared with the prior art, the braking structure of the brake valve provided by the present invention has the following advantages:

[0018] 1. The auxiliary piston divides the inner cavity of the upper valve body into a front cavity and a rear cavity, connecting the brake oil port of the front cavity to the rear wheel brake of the wheeled vehicle and the brake oil port of the rear cavity to the front wheel brake of the wheeled vehicle, so that the brake valve of this application forms two independent braking circuits. Even if one of the braking circuits fails, braking can still be guaranteed, thereby improving braking stability.

[0019] 2. In this application, the longitudinal section of the first sealing ring separating the front cavity and the rear cavity is U-shaped. Utilizing its shape characteristics, the oil in the front cavity is introduced into the U-shaped groove of the first sealing ring through the connecting structure. The first sealing ring is stretched laterally to ensure the sealing between the front cavity and the rear cavity, thereby ensuring braking stability.

[0020] 3. The spring force of compression spring three is greater than that of compression spring two, connecting the rear axle pressure chamber to the rear wheel brake of the wheeled vehicle and the front axle pressure chamber to the front wheel brake of the wheeled vehicle, so that the rear wheel brakes of the car brakes before the front wheel brakes, thereby improving braking stability. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of the brake valve in its initial state.

[0022] Figure 2 yes Figure 1 A magnified view of a portion of the image.

[0023] Figure 3 yes Figure 2 A magnified view of a portion of point A in the middle.

[0024] Figure 4 This is a 3D diagram of the auxiliary piston.

[0025] Figure 5 This is a partial sectional view of the brake valve in braking state one.

[0026] Figure 6 yes Figure 5 A magnified view of a section at point B in the middle.

[0027] Figure 7 This is a partial sectional view of the brake valve in braking state two.

[0028] Figure 8 This is a partial sectional view of the brake valve in its reset state.

[0029] In the diagram, 1. Lower valve body; 2. Upper valve body; 21. Front chamber; 211. Rear axle pressure chamber; 22. Rear chamber; 221. Front axle pressure chamber; 23. Oil inlet; 24. Brake oil port; 25. Shoulder; 251. First limiting surface; 252. Notch; 3. Main piston; 4. Follower piston; 5. Auxiliary piston; 51. First annular groove; 52. Second limiting surface; 53. Contraction section; 54. Guide section; 55. Third limiting surface; 56, sliding section; 561, pressure relief groove; 57, extension section; 58, drainage hole; 6, first sealing ring; 7, drainage gap; 8, second sealing ring; 9, compression spring one; 10, third sealing ring; 11, oil blocking gap; 12, flow limiting element; 121, second annular groove; 13, oil control gap; 14, oil storage gap; 15, compression spring two; 16, compression spring three; 17, oil replenishment chamber. Detailed Implementation

[0030] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0031] like Figure 1 and Figure 2 As shown, the braking structure of this brake valve includes a lower valve body 1 and an upper valve body 2. A main piston 3 is slidably connected inside the lower valve body 1, and a follower piston 4 is slidably connected inside the upper valve body 2. The follower piston 4 abuts against the main piston 3. The braking structure includes an auxiliary piston 5, which is slidably connected inside the upper valve body 2. The inner wall of the upper valve body 2 has an outwardly protruding, annular shoulder 25. One side of the shoulder 25 has a first limiting surface 251 facing the auxiliary piston 5. When the brake valve is in the initial position, one end of the auxiliary piston 5 abuts against the first limiting surface 251, and this end is fitted with a first sealing ring 6 that abuts against the inner wall of the upper valve body 2. The first sealing ring 6 separates the inner cavity of the upper valve body 2 to form a front cavity 21 and a rear cavity 22. The follower piston 4 is located in the front cavity 21. Both the front cavity 21 and the rear cavity 22 have a pair of oil inlets 23 for oil inlet and a brake oil port 24 for high-pressure oil outlet. Figure 5 and Figure 7 As shown, when the follower piston 4 moves toward the auxiliary piston 5, a rear axle pressure chamber 211 for generating braking pressure can be formed in the front chamber 21, and the rear axle pressure chamber 211 is only connected to the corresponding brake oil port 24; when the auxiliary piston 5 moves away from the follower piston 4, a front axle pressure chamber 221 for generating braking pressure can be formed in the rear chamber 22, and the front axle pressure chamber 221 is only connected to the corresponding brake oil port 24.

[0032] like Figure 2As shown, the outer peripheral wall of the auxiliary piston 5 has a first annular groove 51, and the first sealing ring 6 is embedded in the first annular groove 51. The longitudinal section of the first sealing ring 6 is U-shaped, and the opening of the first sealing ring 6 faces the direction of the follower piston 4. The auxiliary piston 5 and the upper valve body 2 have a communication structure connecting the front cavity 21 and the first annular groove 51. The communication structure includes a notch 252 opened on the protruding surface of the shoulder 25, which extends to the first limiting surface 251. The brake oil port 24 of the front cavity 21 communicates with the notch 252. One end of the auxiliary piston 5 has a drainage gap 7 between it and the cavity wall of the upper valve body 2. The drainage gap 7 connects the notch 252 and the first annular groove 51. The groove width of the first annular groove 51 along the axial direction of the auxiliary piston 5 is greater than the thickness of the first sealing ring 6 along the axial direction of the auxiliary piston 5. Figure 5 and Figure 7 As shown, when the auxiliary piston 5 moves away from the follower piston 4, the groove wall of the first annular groove 51 can completely block the opening of the first sealing ring 6.

[0033] The front cavity 21 has an annular second sealing ring 8 on its cavity wall. The second sealing ring 8 is located on the other side of the shoulder 25. When the outer peripheral wall of the follower piston 4 abuts against the inner ring of the second sealing ring 8, the aforementioned rear shaft pressure cavity 211 is formed between the first sealing ring 6 and the second sealing ring 8. Figure 3 and Figure 6 As shown, a compression spring 9 and a third sealing ring 10 are fitted on the end of the auxiliary piston 5 away from the follower piston 4. The longitudinal section of the third sealing ring 10 is D-shaped. The outer ring of the third sealing ring 10 abuts against the cavity wall of the rear cavity 22, and there is a gap between the inner ring of the third sealing ring 10 and the auxiliary piston 5. One end of the compression spring 9 acts on the auxiliary piston 5, and the other end acts on one side of the third sealing ring 10. The auxiliary piston 5 also has a second limiting surface 52. There is an oil-blocking gap 11 between the second limiting surface 52 and the other side of the third sealing ring 10, which communicates with the oil inlet 23 of the rear cavity 22. When the auxiliary piston 5 moves away from the follower piston 4, the second limiting surface 52 can abut against the other side of the third sealing ring 10, so that the end of the auxiliary piston 5 and the rear cavity 22 form the aforementioned front shaft pressure chamber 221.

[0034] like Figure 4 As shown, the auxiliary piston 5 has a cylindrical contraction section 53, a conical guide section 54, and a sliding section 56 that abuts against the cavity wall of the rear cavity 22, as... Figure 3 and Figure 6As shown, the third sealing ring 10 is fitted onto the contraction section 53. The large end face of the guide section 54 is the aforementioned second limiting surface 52. The sliding section 56 is connected to the small end of the guide section 54 to form the third limiting surface 55. The third limiting surface 55 is located at the oil inlet 23 of the rear cavity 22. The guide section 54 is fitted with a flow limiting member 12, which is slidably connected between the third sealing ring 10 and the third limiting surface 55. An oil control gap 13 is formed between the flow limiting member 12 and the guide section 54, connecting the oil inlet 23 of the rear cavity 22 and the oil blocking gap 11. The auxiliary piston 5 has a flow guide hole 58 extending radially from the sliding section 56 to the guide section 54. The flow guide hole 58 connects the oil inlet 23 of the rear cavity 22 and the oil control gap 13. The cross-section of the flow limiting member 12 is annular. The outer end of the flow limiting member 12 is clearance-fitted with the upper valve body 2, and the inner ring of the flow limiting member 12 has a second annular groove 121.

[0035] like Figures 2-4 As shown, the auxiliary piston 5 also has an extension section 57 connected to the sliding section 56. There is an oil storage gap 14 between the extension section 57 and the wall of the rear cavity 22. The sliding section 56 is provided with a pressure relief groove 561 that connects the oil storage gap 14 and the drainage hole 58. The braking structure also includes a compression spring 2 15 located in the front cavity 21. The two ends of the compression spring 2 15 act on the follower piston 4 and the auxiliary piston 5, respectively. The braking structure also includes a compression spring 3 16 located in the rear cavity 22. The two ends of the compression spring 3 16 act on the auxiliary piston 5 and the wall of the rear cavity 22, respectively. The elastic force of the compression spring 3 16 is greater than that of the compression spring 2 15.

[0036] like Figures 1-8As shown, the brake valve of this application is mainly used in engineering vehicles. The rear wheel brakes of engineering vehicles are all connected to the rear axle pressure chamber 211, and the front wheel brakes of engineering vehicles are all connected to the front axle pressure chamber 221. The working principle of this brake valve is as follows: When the driver presses the brake pedal, the lower valve body 1 builds pressure, driving the main piston 3 to move upward. The main piston 3 overcomes the elastic force of the compression spring 15 and drives the follower piston 4 to move synchronously. During the movement, the oil inlet 23 in the front chamber 21 is cut off. The follower piston 4 continues to move, so that the outer wall of the follower piston 4 abuts against the inner ring of the second sealing ring 8. The rear axle pressure chamber 211 is formed in the front chamber 21 between the first sealing ring 6 and the second sealing ring 8. The brake oil in the rear axle pressure chamber 211 is output through the brake oil port 24 of the front chamber 21. At this time, the flow restrictor 12 abuts against the third sealing ring 10 under the action of the oil inlet 23 of the rear chamber 22. The second annular groove 12 1. Increase the oil control gap 13 formed between the flow obstruction component and the flow guide component; the follower piston 4 continues to move, the oil replenishment chamber 17 replenishes the brake oil port 24 of the front chamber 21 with oil, the pressure of the rear axle pressure chamber 211 overcomes the elastic force of the compression spring 16, and drives the auxiliary piston 5 to move. The second limiting surface 52 abuts against the third sealing ring 10, and the third sealing ring 10 abuts against the second limiting surface 52 under the elastic force of the compression spring 9. At this time, the flow obstruction component abuts against the third limiting surface 55, cutting off the oil inlet 23 in the rear chamber 22, so that the end of the auxiliary piston 5 and the rear chamber 22 form the aforementioned front axle pressure chamber 221, and the brake oil in the front axle pressure chamber 221 is output through the brake oil port 24 of the rear chamber 22.

[0037] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

[0038] Although this article uses a lot of terms such as lower valve body 1, upper valve body 2, front chamber 21, rear axle pressure chamber 211, rear chamber 22, front axle pressure chamber 221, oil inlet 23, brake oil port 24, shoulder 25, first limiting surface 251, notch 252, main piston 3, follower piston 4, auxiliary piston 5, first annular groove 51, second limiting surface 52, contraction section 53, guide section 54, third limiting surface 55, sliding section 56, pressure relief groove 561, extension section 57, drainage hole 58, first sealing ring 6, drainage gap 7, second sealing ring 8, compression spring one 9, third sealing ring 10, oil blocking gap 11, flow limiting element 12, second annular groove 121, oil control gap 13, oil storage gap 14, compression spring two 15, compression spring three 16, and oil replenishment chamber 17, the possibility of using other terms cannot be ruled out. The use of these terms is merely for the convenience of describing and explaining the nature of the invention; interpreting them as any additional limitation would be contrary to the spirit of the invention.

Claims

1. A braking structure for a brake valve, the brake valve comprising a lower valve body (1) and an upper valve body (2), wherein a main piston (3) is slidably connected within the lower valve body (1), and a follower piston (4) is slidably connected within the upper valve body (2), the follower piston (4) abutting against the main piston (3), characterized in that, The braking structure includes an auxiliary piston (5), which is slidably connected to the upper valve body (2). The auxiliary piston (5) divides the inner cavity of the upper valve body (2) into a front cavity (21) and a rear cavity (22). The follower piston (4) is located in the front cavity (21). A pair of oil inlets (23) and brake oil ports (24) are provided on the walls of both the front cavity (21) and the rear cavity (22). When the follower piston (4) moves toward the auxiliary piston (5), the auxiliary piston (5) One end of the auxiliary piston (5) can form a rear axle pressure chamber (211) for generating braking pressure between itself and the follower piston (4). The rear axle pressure chamber (211) is only connected to the brake oil port (24) of the front chamber (21). When the auxiliary piston (5) moves away from the follower piston (4), the other end of the auxiliary piston (5) can form a front axle pressure chamber (221) for generating braking pressure between itself and the inner wall of the upper valve body (2). The front axle pressure chamber (221) is only connected to the brake oil port (24) of the front chamber (21). (22) is connected to the brake oil port (24). The auxiliary piston (5) is fitted with a compression spring (9) and a third sealing ring (10) at one end away from the follower piston (4). The outer ring of the third sealing ring (10) abuts against the cavity wall of the rear cavity (22), and there is a gap between the inner ring and the auxiliary piston (5). One end of the compression spring (9) acts on the auxiliary piston (5), and the other end acts on one side of the third sealing ring (10). The auxiliary piston (5) also has a second limiting surface (52). There is an oil-blocking gap (11) between the second limiting surface (52) and the other side of the third sealing ring (10) that is connected to the oil inlet (23) of the rear cavity (22). When the auxiliary piston (5) moves away from the follower piston (4), the second limiting surface (52) can abut against the other side of the third sealing ring (10) so that the end of the auxiliary piston (5) and the inner cavity wall of the upper valve body (2) form the aforementioned front axle pressure chamber (221).

2. The braking structure of the brake valve according to claim 1, characterized in that, The inner wall of the upper valve body (2) has an outwardly protruding and annular shoulder (25). One side of the shoulder (25) has a first limiting surface (251) facing the auxiliary piston (5). One end of the auxiliary piston (5) can abut against the first limiting surface (251), and the end is fitted with a first sealing ring (6) that abuts against the inner wall of the upper valve body (2). The first sealing ring (6) separates the inner cavity of the upper valve body (2) to form the aforementioned front cavity (21) and rear cavity (22).

3. The braking structure of the brake valve according to claim 2, characterized in that, The auxiliary piston (5) has a first annular groove (51) on its outer peripheral wall. The first sealing ring (6) is located in the first annular groove (51). The longitudinal section of the first sealing ring (6) is U-shaped, and the opening of the first sealing ring (6) faces the direction of the follower piston (4). The auxiliary piston (5) and the upper valve body (2) have a communication structure that connects the front cavity (21) and the first annular groove (51).

4. The braking structure of the brake valve according to claim 3, characterized in that, The connecting structure includes a notch (252) opened on the protruding surface of the shoulder (25), the notch (252) extends to the first limiting surface (251), the brake oil port (24) of the front cavity (21) is connected to the notch (252), one end of the auxiliary piston (5) has a drainage gap (7) between it and the cavity wall of the upper valve body (2), the drainage gap (7) connects the notch (252) and the first annular groove (51), the groove width of the first annular groove (51) along the axial direction of the auxiliary piston (5) is greater than the thickness of the first sealing ring (6) along the axial direction of the auxiliary piston (5), when the auxiliary piston (5) moves away from the follower piston (4), the groove wall of the first annular groove (51) can completely block the opening of the first sealing ring (6).

5. The braking structure of the brake valve according to any one of claims 2 to 4, characterized in that, The front cavity (21) is provided with a second sealing ring (8) in the shape of an annular ring. The second sealing ring (8) is located on the other side of the shoulder (25). When the outer peripheral wall of the follower piston (4) abuts against the inner ring of the second sealing ring (8), the rear shaft pressure chamber (211) is formed between one end of the auxiliary piston (5) and the follower piston (4).

6. The braking structure of the brake valve according to any one of claims 1 to 4, characterized in that, The longitudinal section of the third sealing ring (10) is D-shaped.

7. The braking structure of the brake valve according to claim 6, characterized in that, The auxiliary piston (5) has a cylindrical contraction section (53) and a conical guide section (54). The third sealing ring (10) is sleeved on the contraction section (53). The large end face of the guide section (54) is the second limiting surface (52) mentioned above. The auxiliary piston (5) also has a third limiting surface (55) located at the oil inlet (23) of the rear cavity (22). The guide section (54) is sleeved with a flow limiting element (12). The flow limiting element (12) is slidably connected between the third sealing ring (10) and the third limiting surface (55). An oil control gap (13) is formed between the flow limiting element (12) and the guide section (54) to connect the oil inlet (23) of the rear cavity (22) and the oil blocking gap (11).

8. The braking structure of the brake valve according to claim 7, characterized in that, The auxiliary piston (5) also has a sliding section (56) that abuts against the cavity wall of the rear cavity (22). The sliding section (56) is connected to the small end of the guide section (54) to form the third limiting surface (55). The auxiliary piston (5) has a flow hole (58) that extends radially from the sliding section (56) to the guide section (54). The flow hole (58) connects the oil inlet (23) of the rear cavity (22) and the oil control gap (13). The cross-section of the flow limiting element (12) is annular. The outer end of the flow limiting element (12) is clearance-fitted with the upper valve body (2), and the inner ring of the flow limiting element (12) has a second annular groove (121).

9. The braking structure of the brake valve according to claim 8, characterized in that, The auxiliary piston (5) also has an extension section (57) connected to the sliding section (56), and there is an oil storage gap (14) between the extension section (57) and the wall of the rear cavity (22). The sliding section (56) is provided with a pressure relief groove (561) that connects the oil storage gap (14) and the drainage hole (58).

10. The braking structure of the brake valve according to any one of claims 1 to 4, characterized in that, The braking structure also includes a second compression spring (15) located in the front cavity (21), the two ends of which act on the follower piston (4) and the auxiliary piston (5) respectively. The braking structure also includes a third compression spring (16) located in the rear cavity (22), the two ends of which act on the auxiliary piston (5) and the cavity wall of the rear cavity (22) respectively. The elastic force of the third compression spring (16) is greater than that of the second compression spring (15).

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